Struct datafusion_physical_expr::expressions::MaxAccumulator

pub struct MaxAccumulator { /* private fields */ }

An accumulator to compute the maximum value

Implementations

impl MaxAccumulator

pub fn try_new(datatype: &DataType) -> Result<Self>

new max accumulator

Trait Implementations

impl Accumulator for MaxAccumulator

fn update_batch(&mut self, values: &[ArrayRef]) -> Result<()>

Updates the accumulator’s state from a vector of arrays.

fn merge_batch(&mut self, states: &[ArrayRef]) -> Result<()>

updates the accumulator’s state from a vector of states.

fn state(&self) -> Result<Vec<AggregateState>>

Returns the state of the accumulator at the end of the accumulation. in the case of an average on which we track sum and n, this function should return a vector of two values, sum and n.

fn evaluate(&self) -> Result<ScalarValue>

returns its value based on its current state.

fn retract_batch(
    &mut self,
    _values: &[Arc<dyn Array + 'static>]
) -> Result<(), DataFusionError>

Retracts an update (caused by the given inputs) to accumulator’s state. Inverse operation of the update_batch operation. This method must be for accumulators that should support bounded OVER aggregates.

impl Debug for MaxAccumulator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.